Two injured in Paris knife attack near Charlie Hebdo's former office

French firefighters move an injured person into an ambulance near the former offices of the French satirical magazine Charlie Hebdo.

Paris (CNN)Two people were seriously injured in a knife attack Friday near the former offices of French satirical magazine Charlie Hebdo, the site of a 2015 terrorist attack, the Paris police told CNN.

The two victims are in a serious condition but their lives are not in danger, according to the police spokesperson. Police had previously said there were four people wounded in the attack
Not long after the attack, a suspect was arrested near Place de la Bastille, in Paris's 11th district, but the person was not immediately identified by police. French prosecutors have opened up a terror investigation.
    "The main perpetrator has been arrested and is currently in police custody. The second individual was placed in custody for his relations with the main perpetrator," Jean-François Ricard, the national anti-terror prosecutor, said on Friday afternoon.
    Seven people in total have been arrested in connection to the attack, a judicial source told CNN on Friday. That number includes the two suspects Ricard discussed.
    The other five people were arrested at an apartment linked to the attack.
    "Five people present during the search of an apartment likely to have been used by the main suspect were actually arrested and placed in custody," the source told CNN.
    The two victims were on a cigarette break at the time when they were attacked, he added. The victims are employees of French documentary production company Premières Lignes, the firm's founder Paul Moreira told BFM TV.
    Moreira said it "all happened very quickly" and that "a few blows were given to the two people in front of the office." Moreira said the victims were attacked with a "sort of cleaver."
    Director of Premières Lignes Luc Hermann said on France Info TV: "We're journalists. Our job is to inform, not to get attacked like this morning." He criticized what he described as a "total absence of protection of this building since the attacks on Charlie Hebdo."
    Charlie Hebdo offered its "support and solidarity" to their former neighbors and colleagues of Premieres Lignes, and "to those affected by this heinous attack," in a statement on Facebook.
    Annie Hidalgo, mayor of Paris, tweeted a statement Friday condemning the attack. "Through this highly symbolic place, it is once again freedom of expression that is targeted," Hidalgo said. "We must remain vigilant and mobilized to defend this pillar of our Republic and protect our citizens."
    The attack comes amid a trial of suspects alle